The purpose of this research is to determine the relative merits of imipramine, behavior therapy and their combination in the treatment of agoraphobia, phobic neurosis (such as claustrophobia, acrophobia, social phobias, animal phobias) and "mixed" phobia (including some characteristics of agoraphobia and some of phobic neurosis). This will be a double-blind study for the behavior therapy patients and will be single-blind for the supportive therapy patients. There will be a total of 180 adult patients, selected from patients applying to the clinic. Each patient will receive twenty-six weekly phobia treatment sessions. Patients will be assigned, through random selection, to one of the following nine groups: 1. agoraphobia treated with behavior therapy and impramine; 2. agoraphobia treated behavior therapy and placebo; 3. agoraphobia treated with supportive psychotherapy and imipramine; 4. phobic neurosis treated with behavior therapy and imipramine; 5. phobic neurosis treated with behavior therapy and placebo; 6. phobic neurosis treated with supportive psychotherapy and imipramine; 7. "mixed" phobia treated with behavior therapy and impramine; 8. "mixed" phobia treated with behavior therapy and placebo; 9. "mixed" phobia treated with supportive psychotherapy and imipramine.